<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    body{
        background-color:#39f;
    }
    .container{
        margin: 0 auto;
        height: 400px;
        width: 300px;
        background-color: transparent;
        border-radius: 20px;
        overflow: hidden;
        display: flex;
        flex-direction: column;

    }
    .container>div{
        width: 100%;
    }
    .top{
        flex: 1;
        background-color: #396;
    }
    .middle{
        height: 50px;
        position: relative;
        background:radial-gradient(circle at left,transparent 10px,#ccc 10px,#ccc 90%,transparent 10px),
        radial-gradient(circle at right,transparent 10px,#ccc 10px,#ccc 90%,transparent 10px)
    }
    .middle::after{
        content: '';
        position: absolute;
        /* 定位 */
        inset: 50% 10px 0 10px; 
        background: linear-gradient(to left,transparent 0%,transparent 50%,#fff 50%,#fff 100%) repeat-x;
        background-size: 10px 1px;
        z-index: 1;
    }
    .bottom{
        height: 100px;
        background-color: #f90;
    }
</style>
<body>
    <div class="container">
        <div class="top"></div>
        <div class="middle"></div>
        <div class="bottom"></div>
    </div>
</body>
</html>